[Cyanosis in 14-year-old patient. Methemoglobinemia: case report].

The bluish coloration of skin and mucous membranes, called as cyanosis, could be explained by high reduced hemoglobin in the capillaries, or the presence of elevated methemoglobin concentration. It is important to think of methemoglobinemia as a differential diagnosis in a cyanotic patient who does not respond to oxygen administration once cardiorespiratory causes are discarded; since it requires other diagnostic methods and specific treatment. We described a case of cyanosis in a fourteen-year-old adolescent with probable congenital methemoglobinemia. We discussed their probable causes, clinic presentation, diagnosis and treatment.